 /*******************************************************************************
  * Copyright (c) 2004, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal.preferences;

 import java.util.ArrayList ;

 /**
  * @since 3.1
  */
 public abstract class PropertyMapAdapter implements IDynamicPropertyMap {

     private PropertyListenerList listeners;
     private int ignoreCount = 0;
     private ArrayList queuedEvents = new ArrayList ();
     
     /* (non-Javadoc)
      * @see org.eclipse.ui.internal.preferences.IDynamicPropertyMap#addListener(org.eclipse.ui.internal.preferences.IPropertyMapListener)
      */
     public final void addListener(IPropertyMapListener listener) {
         if (listeners == null) {
             listeners = new PropertyListenerList();
             attachListener();
         }
         listeners.add(listener);
     }
     
     /* (non-Javadoc)
      * @see org.eclipse.ui.internal.preferences.IDynamicPropertyMap#removeListener(org.eclipse.ui.internal.preferences.IPropertyMapListener)
      */
     public final void removeListener(IPropertyMapListener listener) {
         if (listeners != null) {
             listeners.remove(listener);
             if (listeners.isEmpty()) {
                 detachListener();
                 listeners = null;
             }
         }
     }

     /* (non-Javadoc)
      * @see org.eclipse.ui.internal.preferences.IPropertyMap#isCommonProperty(java.lang.String)
      */
     public final boolean isCommonProperty(String propertyId) {
         return true;
     }

     /**
      * Detaches all listeners which have been registered with other objects
      *
      * @since 3.1
      */
     public void dispose() {
         if (listeners != null) {
             detachListener();
             listeners = null;
         }
     }
     
     protected final void firePropertyChange(String prefId) {
         if (ignoreCount > 0) {
             queuedEvents.add(prefId);
             return;
         }
         
         if (listeners != null) {
             listeners.firePropertyChange(prefId);
         }
     }
     
     public final void addListener(String [] eventsOfInterest, IPropertyMapListener listener) {
         if (listeners == null) {
             listeners = new PropertyListenerList();
             attachListener();
         }
         listeners.add(eventsOfInterest, listener);
     }
     
     protected final void firePropertyChange(String [] prefIds) {
         if (ignoreCount > 0) {
             for (int i = 0; i < prefIds.length; i++) {
                 queuedEvents.add(prefIds[i]);
             }
             return;
         }

         if (listeners != null) {
             listeners.firePropertyChange(prefIds);
         }
     }
     
     public final void startTransaction() {
         ignoreCount++;
     }
     
     public final void endTransaction() {
         ignoreCount--;
         if (ignoreCount == 0 && !queuedEvents.isEmpty()) {
             if (listeners != null) {
                 listeners.firePropertyChange((String []) queuedEvents.toArray(new String [queuedEvents.size()]));
             }
             queuedEvents.clear();
         }
     }
     
     public boolean equals(Object toCompare) {
         return toCompare instanceof IPropertyMap && PropertyUtil.isEqual(this, (IPropertyMap)toCompare);
     }
     
     protected abstract void attachListener();
     protected abstract void detachListener();
 }

